Carl (john Charles Frederick) Viertel ( 1772 - 1834 ) was a Danish painter. Carl (john Charles Frederick) Viertel s works have been put up for auction numerous times, with realized prices surpassing estimated prices, varying from 900.87 USD for Portræt af møntskriver Altewelt i sort jakke og med hvid halssløjfe in 2005 to 1274.39 USD for Porträtt av friherrinnan Sofia Lovisa Sprengtporten in